The present invention relates to a seismic detecting shut-down valve device in which a fluid path is rapidly closed by a fluid-path opening/closing valve which is moved down by air which is sent into an emergency shut-down cylinder.
There are various types of seismic detecting valve devices in which a fluid-path valve is opened when it detects earthquake which has over a certain seismic intensity, to send compressed air to an emergency shut-down valve which rapidly closes a fluid path.
The known seismic detecting shut-down valve is provided separately from a valve for opening and closing a fluid path. Thus, the structure becomes complicate and expensive, and its installation and maintenance need a lot of time and work.